The present invention relates to a channel display circuit for distinguishing the existence or nonexistence of the signal at a satellite broadcast-receiver.
Generally, a satellite-broadcast receiver receives the satellite signal from a parabola antenna and selects the channel by tuning.
In the past, as shown in FIG. 1 the satellite signal having the channel selected through an channel tuning part 1 is applied to a intermediate-frequency (IF) signal level detector 3 through an IF signal automatic-gain-control amplifier 2(IF signal AGC AMP), and the light emitting diode(LED) is driven by the driver 4 after level detection of an IF signal stating how accurately an antenna is fitted to the satellite signal, is displayed.
But, to find how many channels are occupied by the satellite signal, the channel must be scanned, adjusting the antenna so that the screen appears for a moment on the television(TV) and disappears at once. Also LED driver 4 tunes LEDs on and then turns off at once.
If the screen appears for a moment, there is trouble finding the channel with the screen by up/down operation of channels after the stop of the rotation of the antenna and coming out from the scanning mode. At this time, LEDs are turned on. It is impossible to seek the screen to be displayed shortly without watching TV, the satellite signal is regarded as absent so that the problem passing the satellite without inspection can occur.